Fire investigators had also completed their scene investigation and say there are only two possible causes of the fire.
Detective Dave Checketts said anyone who was in the area at the time of the fire and saw any suspicious activity should contact the Dunedin police or Crimestoppers.
The building was on a quiet residential street and had previously been vandalised.
Neighbours have said there had been issues with people breaking into the building since it was abandoned about two years ago.
The property is owned by Leng Seak Loke, who the Otago Daily Times understands is based overseas and was not able to be contacted yesterday.
His daughter lived at the property after he purchased it about four years ago but it had been vacant since she left two years ago.
Southern Fire and Emergency New Zealand investigator Mark Bredenbeck there were only two possible causes.
Either the fire was deliberately lit or there was an accidental ignition from something like a candle or other naked flame.
